You can find mountain bike forks with 1" threaded (used on most cruisers) steerers.
Some of the early Marzocchi forks allow you to interchange steering tubes and fork legs to ensure a good fit.
You can occasionally find a dual crown fork with 1" threaded on EBay.
You can always find a springer fork for a 1" threaded bike.

Sixgun,
I found a 1" suspension fork with threaded 8" steer tube from an ebay seller called Chasertech, $69.99 + shipping Should you need a 1 1/8" steer tube suspension fork I have a brand new RST also from ebay that will not fit any of my old bikes silver in color, I'll make you a good deal on it.

1. buy a new cruiser that uses a 1 1/8 head tube (possibly a designer bicycle or maybe even a walmart that comes with a shock, probably a crappy shock)
2. Get someone to braze lugs and a new 1 1/8 head tube onto your frame.

I found a 90's rockshox on Ebay for $40, with the 1" tube.

If you're buying used, make sure the tube is long enough to go through your headset stack and frame and not come short of the locknut. If its too long, you can cut it down with a hose clamp and hacksaw and file, or add keyed washers (find junk reflectors and cut off the tabs).

I've looked around and emailed Rockshox and Manitou. I think
RST is the only one making new modern shocks (entry level, not with the damping and lockouts etc)
for 1" bikes. None of the manufacturers care. But Marzocchi might still have some old crown&tube NOS parts for 90's 1 1/8 shocks like the Bombers. I have a 1 1/8 coil&oil and LOVE IT. It has the old style pinch bolt and snap ring crown, and could be used with a replacement crown. After that they went to press fit (cryo-fit aka freeze the parts and press fit).

I did it. 1 1/8" Manitou on a early Schwinn cantilever frame. I did it with high speed rotary grinder to the inside dia. of inner bearing race . very carefully>must be just right. Use small loose ball bearings,2 bags full for the lower bearing. I found a caged bearing for the top bearing. It worked! wasn't easy,turned my cruiser into a big BMX with mx-5 power.